powerpc: Enable kcov

kcov provides kernel coverage data that's useful for fuzzing tools like
syzkaller.

Wire up kcov support on powerpc. Disable kcov instrumentation on the same
files where we currently disable gcov and UBSan instrumentation, plus some
additional exclusions which appear necessary to boot on book3e machines.

Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Tested-by: Daniel Axtens <dja@axtens.net> # e6500
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index ad8e228..5b7945a 100644 (file)
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -130,6 +130,7 @@ config PPC
        select ARCH_HAS_ELF_RANDOMIZE
        select ARCH_HAS_FORTIFY_SOURCE
        select ARCH_HAS_GCOV_PROFILE_ALL
+       select ARCH_HAS_KCOV
        select ARCH_HAS_PHYS_TO_DMA
        select ARCH_HAS_PMEM_API                if PPC64
        select ARCH_HAS_PTE_SPECIAL

diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index 8809e28..cddadcc 100644 (file)
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -143,19 +143,29 @@ endif
 obj-$(CONFIG_EPAPR_PARAVIRT)   += epapr_paravirt.o epapr_hcalls.o
 obj-$(CONFIG_KVM_GUEST)                += kvm.o kvm_emul.o
 
-# Disable GCOV & sanitizers in odd or sensitive code
+# Disable GCOV, KCOV & sanitizers in odd or sensitive code
 GCOV_PROFILE_prom_init.o := n
+KCOV_INSTRUMENT_prom_init.o := n
 UBSAN_SANITIZE_prom_init.o := n
 GCOV_PROFILE_machine_kexec_64.o := n
+KCOV_INSTRUMENT_machine_kexec_64.o := n
 UBSAN_SANITIZE_machine_kexec_64.o := n
 GCOV_PROFILE_machine_kexec_32.o := n
+KCOV_INSTRUMENT_machine_kexec_32.o := n
 UBSAN_SANITIZE_machine_kexec_32.o := n
 GCOV_PROFILE_kprobes.o := n
+KCOV_INSTRUMENT_kprobes.o := n
 UBSAN_SANITIZE_kprobes.o := n
 GCOV_PROFILE_kprobes-ftrace.o := n
+KCOV_INSTRUMENT_kprobes-ftrace.o := n
 UBSAN_SANITIZE_kprobes-ftrace.o := n
 UBSAN_SANITIZE_vdso.o := n
 
+# Necessary for booting with kcov enabled on book3e machines
+KCOV_INSTRUMENT_cputable.o := n
+KCOV_INSTRUMENT_setup_64.o := n
+KCOV_INSTRUMENT_paca.o := n
+
 extra-$(CONFIG_PPC_FPU)                += fpu.o
 extra-$(CONFIG_ALTIVEC)                += vector.o
 extra-$(CONFIG_PPC64)          += entry_64.o

diff --git a/arch/powerpc/kernel/trace/Makefile b/arch/powerpc/kernel/trace/Makefile
index b1725ad..8585037 100644 (file)
--- a/arch/powerpc/kernel/trace/Makefile
+++ b/arch/powerpc/kernel/trace/Makefile
@@ -23,6 +23,7 @@ obj-$(CONFIG_TRACING)                 += trace_clock.o
 obj-$(CONFIG_PPC64)                    += $(obj64-y)
 obj-$(CONFIG_PPC32)                    += $(obj32-y)
 
-# Disable GCOV & sanitizers in odd or sensitive code
+# Disable GCOV, KCOV & sanitizers in odd or sensitive code
 GCOV_PROFILE_ftrace.o := n
+KCOV_INSTRUMENT_ftrace.o := n
 UBSAN_SANITIZE_ftrace.o := n

diff --git a/arch/powerpc/kernel/vdso32/Makefile b/arch/powerpc/kernel/vdso32/Makefile
index 50112d4..ce199f6 100644 (file)
--- a/arch/powerpc/kernel/vdso32/Makefile
+++ b/arch/powerpc/kernel/vdso32/Makefile
@@ -23,6 +23,7 @@ targets := $(obj-vdso32) vdso32.so vdso32.so.dbg
 obj-vdso32 := $(addprefix $(obj)/, $(obj-vdso32))
 
 GCOV_PROFILE := n
+KCOV_INSTRUMENT := n
 UBSAN_SANITIZE := n
 
 ccflags-y := -shared -fno-common -fno-builtin

diff --git a/arch/powerpc/kernel/vdso64/Makefile b/arch/powerpc/kernel/vdso64/Makefile
index 69cecb3..28e7d11 100644 (file)
--- a/arch/powerpc/kernel/vdso64/Makefile
+++ b/arch/powerpc/kernel/vdso64/Makefile
@@ -9,6 +9,7 @@ targets := $(obj-vdso64) vdso64.so vdso64.so.dbg
 obj-vdso64 := $(addprefix $(obj)/, $(obj-vdso64))
 
 GCOV_PROFILE := n
+KCOV_INSTRUMENT := n
 UBSAN_SANITIZE := n
 
 ccflags-y := -shared -fno-common -fno-builtin

diff --git a/arch/powerpc/mm/Makefile b/arch/powerpc/mm/Makefile
index ee1efa3..d52ec11 100644 (file)
--- a/arch/powerpc/mm/Makefile
+++ b/arch/powerpc/mm/Makefile
@@ -47,3 +47,8 @@ obj-$(CONFIG_PPC_COPRO_BASE)  += copro_fault.o
 obj-$(CONFIG_SPAPR_TCE_IOMMU)  += mmu_context_iommu.o
 obj-$(CONFIG_PPC_PTDUMP)       += ptdump/
 obj-$(CONFIG_PPC_MEM_KEYS)     += pkeys.o
+
+# Disable kcov instrumentation on sensitive code
+# This is necessary for booting with kcov enabled on book3e machines
+KCOV_INSTRUMENT_tlb_nohash.o := n
+KCOV_INSTRUMENT_fsl_booke_mmu.o := n

diff --git a/arch/powerpc/xmon/Makefile b/arch/powerpc/xmon/Makefile
index 878f9c1..3050f93 100644 (file)
--- a/arch/powerpc/xmon/Makefile
+++ b/arch/powerpc/xmon/Makefile
@@ -5,6 +5,7 @@
 subdir-ccflags-y := $(call cc-disable-warning, builtin-requires-header)
 
 GCOV_PROFILE := n
+KCOV_INSTRUMENT := n
 UBSAN_SANITIZE := n
 
 # Disable ftrace for the entire directory